BETA-MICROGLOBULIN IN CEREBROSPINAL-FLUID IN NEUROLOGY

Objectives: beta 2-microglobulin (beta 2-m) is a small molecular weigh t protein (11 800 Daltons) which can transudate into the cerebrospinal fluid (CSF) in the same manner than albumin. Intrathecal synthesis is a sign of local immuno-stimulation and is correlated with immunoglobu lin G. The aim of this study was to ascertain the relationship between beta 2-microglobulin levels in the CSF and neurological diseases. Met hods: beta 2-microglobulin was assayed in the CSF and blood using an i mmunoenzyme method in 64 patients with multiple sclerosis (n=14), huma n immunodeficiency virus (HIV) infection (n=5), meningitis (n=12) or a peripheral neurological disease (n=10) and in 7 control subjects. Res ults: There was no overall correlation between beta 2-m in the CSF and blood levels (r=0.35). In controls, beta 2-m CSF and blood levels wer e respectively 0.94+/-0.22 and 1.46+/-0.83 mg/l, beta 2-m was signific antly higher in the CSF of patients with meningitis and in the HIV pos itive patients (4+/-3.5 and 3.69+/-2.06 mg/l respectively) (p < 0.05). Type of meningitis (bacterial or non-bacterial) had no effect on the CSF level. For the HIV patients, the CSF/blood ratio for beta 2-m was similar to that in controls due to a rise in both blood and CSF, Final ly, in patients with multiple sclerosis, there was no significant chan ge in CSF level of beta 2-m. Conclusion: beta 2-microglobulin in cereb rospinal fluid was not found to be correlated with the neurological di seases studied and cannot be used as a diagnostic test.